This invention, in its preferred form, relates to tape electrodes for application to the outer layer of skin of the human body, particularly those capable of injecting electrical energy into the human body. More particularly, the invention provides an improved lead wire connector for such electrodes which permits long periods of usage and freedom of movement of the body when the electrode is in place.
When electrodes are utilized with devices, such as transcutaneous electrical nerve stimulators and the like which inject significant energy into the human body, as distinguished from monitoring electrodes, a number of factors must be considered. Such electrodes should be capable of remaining attached to the body for extended periods of time, such as several days, while allowing the subject wearing the electrode to engage in normal activities. In addition, the electrode must not encourage the growth of bacteria or other micro-organisms between the area of the electrode and the skin. Further, the electrode must be capable of distributing the transmitted electrical energy over a relatively broad area of the skin so as to avoid local energy concentrations, or "hot" spots which might cause discomfort to the subject. Finally, the electrode must be made of materials which are non-allergenic, must be easy to apply and must make good physical and electrical contact with both the electrial lead wire and the skin of the subject. One preferred type of tape electrode material for this purpose is described in the United States patent of Charles V. Burton, U.S. Pat. No. 4,008,721, dated Feb. 2, 1977 and entitled TAPE ELECTRODE FOR TRANSMITTING ELECTRICAL SIGNALS THROUGH THE SKIN, which patent is assigned to the present assignee hereof. Other types of electrodes of this kind have been described in the references cited in the aforementioned Burton patent and in U.S. patent application Ser. No. 674,176 filed Apr. 5, 1976, for TAPE ELECTRODE, now issued as U.S. Pat. No. 4,067,342 on Jan. 10, 1978 in the name of Charles V. Burton and assigned to the present assignee hereof.
When providing a means for connecting the electrical lead wire to the tape electrode, it must be borne in mind that the lead wire must make contact with the conductive side of the electrode and at the same time should not make direct electrical contact with the skin. In addition, the entire skin area beneath the electrode should receive substantially evenly distributed amounts of energy. Thus, any electrically "blank" spots on the conductive surface of the electrode are to be avoided.